STEREO SWG 2009, October , New Hampshire Kinematical Characterization of Intensity Fluctuations Observed in STEREO EUVI Images Katherine Baldwin Praxis, Inc. / NRL Guillermo Stenborg Interferometrics, Inc. / NRL Angelos Vourlidas, Russ Howard Naval Research Lab (NRL) STEREO SWG 2009, October , New Hampshire Motivation - What have other instruments seen? Wave Interpretation Mass Outflow Interpretation Why STEREO EUVI? It is possible to track the traveling intensity variations Wavelet Processing De-rotation Feature Tracking Height-Time Map Creation Kinematical Characterization Future Work 3D reconstruction of features true speeds Magnetic topology Issues Outline STEREO SWG 2009, October , New Hampshire Motivation - Robbrecht Waves May 13th, 1998 JOP Campaign. Slow Magnetoacoustic Waves in Coronal Loops: EIT and TRACE E. Robbrecht, E. Verwichte, D. Berghmans, J. Hochedez, S. Poedts, V. Nakariakov A&A, Vol 370, pp , Telescopes: SOHO/EIT and TRACE Projected Speed: km/s True Speed: ?? STEREO SWG 2009, October , New Hampshire Motivation - Doschek Outflows Outflows from the Sun somehow make up the slow solar wind. Doppler-shifted EIS measurements to validate result. Also, analyzes a Dec 11, 2007 AR. Top: FeXII A intensity for August 23, 2007 AR Bottom: Doppler Map (blue is towards the observer) obtained with the Extreme- ultraviolet Imaging Spectrometer (EIS) on the Hinode S/C. Flows and Non-thermal Velocities in Solar Active Regions Observed with Hinode/EIS: A Tracer of Active Region Sources of Heliospheric Magnetic Fields? G. Doschek, H. Warren, J. Mariska, K. Muglach, J. Culhane, H. Hara, T. Watanabe ApJ, Vol 686, pp , Telescope: HINODE/EIS LOS Speed: km/s True Speed: ? STEREO SWG 2009, October , New Hampshire Motivation - Harra Outflows Outflows at the Edges of Active Regions: Contributions to Solar Wind Formation? L. Harra, T. Sakao, C. Mandrini, H. Hara, S. Imada, P. Young, L. Van Driel-Gesztelyi, D. Baker ApJ, Vol 676, pp. L147-L150, Telescope: Hinode/XRT LOS Speed: km/s True Speed: >100 km/s The outflows are the major contributor to the slow solar wind. Outflow occurs at EDGES of active regions. Large scale loops lie over active region and open to interplanetary space. Doppler shifted EIS measurements were used as comparison. STEREO SWG 2009, October , New Hampshire Motivation - Marsch Outflows Photospheric convection drives a global coronal circulation. Most blue shifted occurrences are associated with open or large looped field lines. Agrees with Harra et al. - mass outflow is contributing to the slow solar wind through open field lines. Using force-free magnetic field model to define open/closed lines. Loops of specified height (~100,000km) are considered open field lines. Plasma Flows Guided by Strong Magnetic Fields in the Solar Corona E. Marsch, H. Tian, J. Sun, W. Curdt, T. Wiegelmann ApJ, Vol 685, pp , Telescope : Hinode/EIS Contours : Force-free magnetic field model LOS Speed: ?? True Speed: ?? STEREO SWG 2009, October , New Hampshire STEREO Advantage Continuous coverage: EUVI data does not suffer from small FOV/telemetry problems of Hinode payload. Suitable temporal resolution Constant bandpass allows us to follow brightness fluctuations directly, without using Doppler analysis. 3D capabilities allow true speed calculations. Why STEREO/EUVI ? STEREO SWG 2009, October , New Hampshire EUVI 171 B Running difference of wavelet-cleaned images Cadence: 1.5 min Details of the wavelet-cleaning and -enhancing algorithm at A Fresh View of the Extreme-Ultraviolet Corona from the Application of a New Image-Processing Technique Stenborg, G.; Vourlidas, A.; Howard, R. ApJ, Vol 674, Issue 2, pp March 25, 2008 Does STEREO/EUVI see something similar? A few words on the wavelet technique STEREO SWG 2009, October , New Hampshire What does STEREO/EUVI observe on February 20, 2007 Outflows at the Edges of Active Regions: Contributions to Solar Wind Formation? L. Harra, T. Sakao, C. Mandrini, H. Hara, S. Imada, P. Young, L. Van Driel-Gesztelyi, D. Baker ApJ, Vol 676, pp. L147-L150, EUVI B 195 wavelet processed snapshot movie ( time span 8 hs, cadence 10 min ) of a comparable area to that observed by HINODE/XRT HINODE/XRT STEREO SWG 2009, October , New Hampshire Top: FeXII A intensity Bottom: Doppler Map (blue is towards the observer) obtained with Hinode/EIS. August 23, 2007 Full-Disk EUVI B 195 ( 06:55 UT ) wavelet processed intensity image From Doschek, et al., ApJ, 686, 1362, 2008 EUVI B 195 ( 06:55 UT ) wavelet processed snapshot of the disk region shown in Doschek et al paper STEREO SWG 2009, October , New Hampshire Top: FeXII A intensity Bottom: Doppler Map (blue is towards the observer) obtained with the HINODE/EIS. EUVI B 195: December 11, 2007 AR (03:35 UT) Also from Doschek, et al., ApJ, 686, 1362, 2008 December 11, 2007 STEREO SWG 2009, October , New Hampshire Harra et al., ApJ Letters, 2008 Active Region seen on Feb 2007 Active Regions seen on 06 Jun 2007 and 25 Mar 2008 will be considered good candidates for this study, as well. same dates! Active Region seen on Feb 2007 Marsch et al., ApJ, 2008 Telescope: EIS Telescope: XRT Doschek et al., ApJ, 2008 Active Region seen on 23 Aug 2007 Active Region seen on 11 Dec 2007 Telescope: EIS Recapitulation STEREO SWG 2009, October , New Hampshire How can we measure the speed of the disturbances? Original idea: Use of Height-Time Maps (J-maps) Sheeley et al. 1999, 2000 available in solar software 2008/03/25 EUVI B /02/20 EUVI B /08/23 EUVI B /12/09 EUVI B 171 STEREO SWG 2009, October , New Hampshire 1)Wavelet-processed images are de-rotated by 8 hour segments. 2)Paths manually defined by point-and-click on the Region of Interest 3)K-maps created through each 8 hour segments. K maps Using the K-maps we are able to find the projected speed of the density enhancements. Before speed assessment we determine if tracked features remain constant throughout the 8 hour de-rotation period. If not constant, then speed cannot reliably be found. S/C A Distance along the path Time STEREO SWG 2009, October , New Hampshire Kinematical characterization December 9, 2007 [00:00 UT - 08:00 UT] 95 km/s 120 km/s 115 km/s 100 km/s 95 km/s --- Projected Speed of a sample of intensity variations as they move along the selected ray ---- * On the intensity variations observed along pseudo-open field lines nearby AR A qualitative analysis of the days processed so far showed that, the traveling disturbances are stronger (i.e., better discerned against the background) when: i) closed field lines are nearby apparently open field lines, ii) closed field lines are nearby another closed field lines that end up on different foot points. Example of quantitative analysis The seven cases analyzed (including on-disk and off-limb cases) result in projected speeds in the range km/s STEREO SWG 2009, October , New Hampshire Future Work: I) Tie-Point to infer the true speed? STEREO SWG 2009, October , New Hampshire Future Work: II) Magnetic Topology Do these intensity variations exist anywhere else on the disk with closed field lines? Do the variation exist along plumes with open field lines? How does magnetic topology relate to flow strengths? Infer the topology of the magnetic field where the flows are observed by comparing with magnetic field models STEREO SWG 2009, October , New Hampshire Reliability of feature tracking using point-and-click method Accuracy of feature tracking between STEREO-A to STEREO-B Are the flows inside closed (but long) loops or inside open magnetic field extending into the heliosphere? Physical Interpretation: Are the observed intensity fluctuations mass outflows or waves? How is the magnetic field topology where the intensity fluctuations exist? Are the observed intensity fluctuations observed above the polar coronal holes caused by the same mechanism as those observed in pseudo-open field lines nearby AR? Issues to Consider STEREO SWG 2009, October , New Hampshire Wavelet scales 1 to 4 (W i ) 2D B 3 -spline For comparison, smoothed image corresponding to decomposition based on 50 scales Smoothed image corresponding to decomposition based on 25 scales The 2D a trous algorithm Back